Simple APRS Transmitter

I started to work on a simple APRS transmitter today so that I could use it as a antenna test bed for Project Swift.

It was very simple to build using only an Arduino Uno, a Venus GPS receiver a Radiometrix HX1 module (on 144.800Mhz) and an SMA PCB socket.

The completed board looks like this…

After playing around all day with the APRS message format, I managed to get it working and updating to aprs.fi via my own igate.

Next up will be a test with it installed in the car.

Basic pan & tilt platform

The pan and tilt platform will hold the high gain yagi used for receiving the HAB signal.

I’ve just got a small, simple platform for now to test with and will upgrade it once everything is working well. It’s driven with 2 hobby servos direct from the Arduino. One minor drawback is that a standard hobby servo only has a round 90 degrees of movement. That is fine for the tilt control but no good for the pan control so I will have to try and source a servo capable of 360 degree rotation that provides position feedback or maybe build a 4:1 drive system for a standard servo.
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Sparkfun ProtoShield

Just a quick post about the Sparkfun ProtoShield v2 board that I have to help make building HABAT easier.

The board comes in kit form and needs a small amount of soldering to get it ready for use. It’s an easy job with 3 small resisters, 2 small capacitors, 2 LED’s, 2 switches and 4 Arduino header pins.

Here is the completed board:
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